PARIS - US Secretary of State John Kerry will travel to the Vatican to meet a top aide to Pope Francis for talks on Tuesday on the Middle East and other foreign policy issues, the State Department said.

Kerry is to meet Secretary of State of the Holy See Pietro Parolin "to discuss foreign policy priorities, including Pope Francis' vocal leadership on the Middle East peace process, poverty, and humanitarian issues", spokeswoman Jen Psaki said in a statement.

In his first "State of the World" address on Monday to diplomats accredited to the Vatican, Francis called for renewed political will to end the conflict in Syria and lamented a "general indifference" to the plight of refugees around the world.

After the stop at the Vatican, he is due to attend an international donors' conference for Syria in Kuwait City on Wednesday.